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Annotation of previous_trunk/src/slirp/tcp_var.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1982, 1986, 1993, 1994
        !             3:  *     The Regents of the University of California.  All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms, with or without
        !             6:  * modification, are permitted provided that the following conditions
        !             7:  * are met:
        !             8:  * 1. Redistributions of source code must retain the above copyright
        !             9:  *    notice, this list of conditions and the following disclaimer.
        !            10:  * 2. Redistributions in binary form must reproduce the above copyright
        !            11:  *    notice, this list of conditions and the following disclaimer in the
        !            12:  *    documentation and/or other materials provided with the distribution.
        !            13:  * 3. Neither the name of the University nor the names of its contributors
        !            14:  *    may be used to endorse or promote products derived from this software
        !            15:  *    without specific prior written permission.
        !            16:  *
        !            17:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            18:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            19:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            20:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            21:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            22:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            23:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            24:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            25:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            26:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            27:  * SUCH DAMAGE.
        !            28:  *
        !            29:  *     @(#)tcp_var.h   8.3 (Berkeley) 4/10/94
        !            30:  * tcp_var.h,v 1.3 1994/08/21 05:27:39 paul Exp
        !            31:  */
        !            32: 
        !            33: #ifndef _TCP_VAR_H_
        !            34: #define _TCP_VAR_H_
        !            35: 
        !            36: #include "tcpip.h"
        !            37: #include "tcp_timer.h"
        !            38: 
        !            39: /*
        !            40:  * Tcp control block, one per tcp; fields:
        !            41:  */
        !            42: struct tcpcb {
        !            43:        struct tcpiphdr *seg_next;      /* sequencing queue */
        !            44:        struct tcpiphdr *seg_prev;
        !            45:        short   t_state;                /* state of this connection */
        !            46:        short   t_timer[TCPT_NTIMERS];  /* tcp timers */
        !            47:        short   t_rxtshift;             /* log(2) of rexmt exp. backoff */
        !            48:        short   t_rxtcur;               /* current retransmit value */
        !            49:        short   t_dupacks;              /* consecutive dup acks recd */
        !            50:        u_short t_maxseg;               /* maximum segment size */
        !            51:        char    t_force;                /* 1 if forcing out a byte */
        !            52:        u_short t_flags;
        !            53: #define        TF_ACKNOW       0x0001          /* ack peer immediately */
        !            54: #define        TF_DELACK       0x0002          /* ack, but try to delay it */
        !            55: #define        TF_NODELAY      0x0004          /* don't delay packets to coalesce */
        !            56: #define        TF_NOOPT        0x0008          /* don't use tcp options */
        !            57: #define        TF_SENTFIN      0x0010          /* have sent FIN */
        !            58: #define        TF_REQ_SCALE    0x0020          /* have/will request window scaling */
        !            59: #define        TF_RCVD_SCALE   0x0040          /* other side has requested scaling */
        !            60: #define        TF_REQ_TSTMP    0x0080          /* have/will request timestamps */
        !            61: #define        TF_RCVD_TSTMP   0x0100          /* a timestamp was received in SYN */
        !            62: #define        TF_SACK_PERMIT  0x0200          /* other side said I could SACK */
        !            63: 
        !            64:        /* Make it static  for now */
        !            65: /*     struct  tcpiphdr *t_template;   / * skeletal packet for transmit */
        !            66:        struct  tcpiphdr t_template;
        !            67: 
        !            68:        struct  socket *t_socket;               /* back pointer to socket */
        !            69: /*
        !            70:  * The following fields are used as in the protocol specification.
        !            71:  * See RFC783, Dec. 1981, page 21.
        !            72:  */
        !            73: /* send sequence variables */
        !            74:        tcp_seq snd_una;                /* send unacknowledged */
        !            75:        tcp_seq snd_nxt;                /* send next */
        !            76:        tcp_seq snd_up;                 /* send urgent pointer */
        !            77:        tcp_seq snd_wl1;                /* window update seg seq number */
        !            78:        tcp_seq snd_wl2;                /* window update seg ack number */
        !            79:        tcp_seq iss;                    /* initial send sequence number */
        !            80:        u_int32_t snd_wnd;              /* send window */
        !            81: /* receive sequence variables */
        !            82:        u_int32_t rcv_wnd;              /* receive window */
        !            83:        tcp_seq rcv_nxt;                /* receive next */
        !            84:        tcp_seq rcv_up;                 /* receive urgent pointer */
        !            85:        tcp_seq irs;                    /* initial receive sequence number */
        !            86: /*
        !            87:  * Additional variables for this implementation.
        !            88:  */
        !            89: /* receive variables */
        !            90:        tcp_seq rcv_adv;                /* advertised window */
        !            91: /* retransmit variables */
        !            92:        tcp_seq snd_max;                /* highest sequence number sent;
        !            93:                                         * used to recognize retransmits
        !            94:                                         */
        !            95: /* congestion control (for slow start, source quench, retransmit after loss) */
        !            96:        u_int32_t snd_cwnd;             /* congestion-controlled window */
        !            97:        u_int32_t snd_ssthresh;         /* snd_cwnd size threshold for
        !            98:                                         * for slow start exponential to
        !            99:                                         * linear switch
        !           100:                                         */
        !           101: /*
        !           102:  * transmit timing stuff.  See below for scale of srtt and rttvar.
        !           103:  * "Variance" is actually smoothed difference.
        !           104:  */
        !           105:        short   t_idle;                 /* inactivity time */
        !           106:        short   t_rtt;                  /* round trip time */
        !           107:        tcp_seq t_rtseq;                /* sequence number being timed */
        !           108:        short   t_srtt;                 /* smoothed round-trip time */
        !           109:        short   t_rttvar;               /* variance in round-trip time */
        !           110:        u_short t_rttmin;               /* minimum rtt allowed */
        !           111:        u_int32_t max_sndwnd;           /* largest window peer has offered */
        !           112: 
        !           113: /* out-of-band data */
        !           114:        char    t_oobflags;             /* have some */
        !           115:        char    t_iobc;                 /* input character */
        !           116: #define        TCPOOB_HAVEDATA 0x01
        !           117: #define        TCPOOB_HADDATA  0x02
        !           118:        short   t_softerror;            /* possible error not yet reported */
        !           119: 
        !           120: /* RFC 1323 variables */
        !           121:        u_char  snd_scale;              /* window scaling for send window */
        !           122:        u_char  rcv_scale;              /* window scaling for recv window */
        !           123:        u_char  request_r_scale;        /* pending window scaling */
        !           124:        u_char  requested_s_scale;
        !           125:        u_int32_t       ts_recent;              /* timestamp echo data */
        !           126:        u_int32_t       ts_recent_age;          /* when last updated */
        !           127:        tcp_seq last_ack_sent;
        !           128: 
        !           129: };
        !           130: 
        !           131: #define        sototcpcb(so)   ((so)->so_tcpcb)
        !           132: 
        !           133: /*
        !           134:  * The smoothed round-trip time and estimated variance
        !           135:  * are stored as fixed point numbers scaled by the values below.
        !           136:  * For convenience, these scales are also used in smoothing the average
        !           137:  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
        !           138:  * With these scales, srtt has 3 bits to the right of the binary point,
        !           139:  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
        !           140:  * binary point, and is smoothed with an ALPHA of 0.75.
        !           141:  */
        !           142: #define        TCP_RTT_SCALE           8       /* multiplier for srtt; 3 bits frac. */
        !           143: #define        TCP_RTT_SHIFT           3       /* shift for srtt; 3 bits frac. */
        !           144: #define        TCP_RTTVAR_SCALE        4       /* multiplier for rttvar; 2 bits */
        !           145: #define        TCP_RTTVAR_SHIFT        2       /* multiplier for rttvar; 2 bits */
        !           146: 
        !           147: /*
        !           148:  * The initial retransmission should happen at rtt + 4 * rttvar.
        !           149:  * Because of the way we do the smoothing, srtt and rttvar
        !           150:  * will each average +1/2 tick of bias.  When we compute
        !           151:  * the retransmit timer, we want 1/2 tick of rounding and
        !           152:  * 1 extra tick because of +-1/2 tick uncertainty in the
        !           153:  * firing of the timer.  The bias will give us exactly the
        !           154:  * 1.5 tick we need.  But, because the bias is
        !           155:  * statistical, we have to test that we don't drop below
        !           156:  * the minimum feasible timer (which is 2 ticks).
        !           157:  * This macro assumes that the value of TCP_RTTVAR_SCALE
        !           158:  * is the same as the multiplier for rttvar.
        !           159:  */
        !           160: #define        TCP_REXMTVAL(tp) \
        !           161:        (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
        !           162: 
        !           163: /*
        !           164:  * TCP statistics.
        !           165:  * Many of these should be kept per connection,
        !           166:  * but that's inconvenient at the moment.
        !           167:  */
        !           168: struct tcpstat {
        !           169:        u_long  tcps_connattempt;       /* connections initiated */
        !           170:        u_long  tcps_accepts;           /* connections accepted */
        !           171:        u_long  tcps_connects;          /* connections established */
        !           172:        u_long  tcps_drops;             /* connections dropped */
        !           173:        u_long  tcps_conndrops;         /* embryonic connections dropped */
        !           174:        u_long  tcps_closed;            /* conn. closed (includes drops) */
        !           175:        u_long  tcps_segstimed;         /* segs where we tried to get rtt */
        !           176:        u_long  tcps_rttupdated;        /* times we succeeded */
        !           177:        u_long  tcps_delack;            /* delayed acks sent */
        !           178:        u_long  tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
        !           179:        u_long  tcps_rexmttimeo;        /* retransmit timeouts */
        !           180:        u_long  tcps_persisttimeo;      /* persist timeouts */
        !           181:        u_long  tcps_keeptimeo;         /* keepalive timeouts */
        !           182:        u_long  tcps_keepprobe;         /* keepalive probes sent */
        !           183:        u_long  tcps_keepdrops;         /* connections dropped in keepalive */
        !           184: 
        !           185:        u_long  tcps_sndtotal;          /* total packets sent */
        !           186:        u_long  tcps_sndpack;           /* data packets sent */
        !           187:        u_long  tcps_sndbyte;           /* data bytes sent */
        !           188:        u_long  tcps_sndrexmitpack;     /* data packets retransmitted */
        !           189:        u_long  tcps_sndrexmitbyte;     /* data bytes retransmitted */
        !           190:        u_long  tcps_sndacks;           /* ack-only packets sent */
        !           191:        u_long  tcps_sndprobe;          /* window probes sent */
        !           192:        u_long  tcps_sndurg;            /* packets sent with URG only */
        !           193:        u_long  tcps_sndwinup;          /* window update-only packets sent */
        !           194:        u_long  tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */
        !           195: 
        !           196:        u_long  tcps_rcvtotal;          /* total packets received */
        !           197:        u_long  tcps_rcvpack;           /* packets received in sequence */
        !           198:        u_long  tcps_rcvbyte;           /* bytes received in sequence */
        !           199:        u_long  tcps_rcvbadsum;         /* packets received with ccksum errs */
        !           200:        u_long  tcps_rcvbadoff;         /* packets received with bad offset */
        !           201: /*     u_long  tcps_rcvshort;  */      /* packets received too short */
        !           202:        u_long  tcps_rcvduppack;        /* duplicate-only packets received */
        !           203:        u_long  tcps_rcvdupbyte;        /* duplicate-only bytes received */
        !           204:        u_long  tcps_rcvpartduppack;    /* packets with some duplicate data */
        !           205:        u_long  tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
        !           206:        u_long  tcps_rcvoopack;         /* out-of-order packets received */
        !           207:        u_long  tcps_rcvoobyte;         /* out-of-order bytes received */
        !           208:        u_long  tcps_rcvpackafterwin;   /* packets with data after window */
        !           209:        u_long  tcps_rcvbyteafterwin;   /* bytes rcvd after window */
        !           210:        u_long  tcps_rcvafterclose;     /* packets rcvd after "close" */
        !           211:        u_long  tcps_rcvwinprobe;       /* rcvd window probe packets */
        !           212:        u_long  tcps_rcvdupack;         /* rcvd duplicate acks */
        !           213:        u_long  tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
        !           214:        u_long  tcps_rcvackpack;        /* rcvd ack packets */
        !           215:        u_long  tcps_rcvackbyte;        /* bytes acked by rcvd acks */
        !           216:        u_long  tcps_rcvwinupd;         /* rcvd window update packets */
        !           217: /*     u_long  tcps_pawsdrop;  */      /* segments dropped due to PAWS */
        !           218:        u_long  tcps_predack;           /* times hdr predict ok for acks */
        !           219:        u_long  tcps_preddat;           /* times hdr predict ok for data pkts */
        !           220:        u_long  tcps_socachemiss;       /* tcp_last_so misses */
        !           221:        u_long  tcps_didnuttin;         /* Times tcp_output didn't do anything XXX */
        !           222: };
        !           223: 
        !           224: extern struct  tcpstat tcpstat;        /* tcp statistics */
        !           225: extern u_int32_t       tcp_now;                /* for RFC 1323 timestamps */
        !           226: 
        !           227: #endif

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